Articles comprising broad molecular weight distribution polypropylene resins

Patent metadata

Field	Value
Publication number	US-9902822-B2
Application number	US-201314434808-A
Country	US
Kind code	B2
Filing date	Oct 8, 2013
Priority date	Oct 31, 2012
Publication date	Feb 27, 2018
Grant date	Feb 27, 2018

Abstract

Disclosed herein are embodiments of films which comprise a polypropylene resin comprising at least 50 mol % propylene, an MWD (Mw/Mn) of greater than 5, a branching index (g′) of at least 0.95, and a melt strength of at least 20 cN determined using an extensional rheometer at 190° C. A method of making a film is also disclosed.

First claim

We claim:

1. A film comprising a polypropylene resin, wherein the polypropylene resin comprises at least 50 mol % propylene, an MWD (Mw/Mn) greater than 5, a branching index (g′) of at least 0.95, and a melt strength greater than 20 cN determined using an extensional rheometer at 190° C., wherein the film is an extruded blown film, a cast film, or a combination thereof, wherein the polypropylene resin is produced by contacting propylene monomers at propylene polymerization conditions with a catalyst system comprising a Ziegler-Natta catalyst comprising a non-aromatic internal electron donor, and first and second external electron donors comprising different organosilicon compounds.

2. The film of claim 1 , wherein the polypropylene resin has an MWD from 6 to 15 and an MFR from 0.1 to 100, determined according to ASTM D1238 Condition L.

3. The film of claim 1 , wherein the melt strength of the polypropylene resin is from 50 cN to 200 cN.

4. The film of claim 1 , wherein the polypropylene resin has a viscosity ratio of from 35 to 80 determined from the complex viscosity ratio at 0.01 to 100 rad/s angular frequency at a fixed strain of 10% at 190° C.

5. The film of claim 1 , wherein the polypropylene resin has a heat distortion temperature of greater than or equal to 100° C., determined according to ASTM D648 using a load of 0.45 MPa (66 psi).

6. The film of claim 1 , wherein the polypropylene resin has a stiffness of from 2000 MPa (290 kpsi) to 2500 MPa (360 kpsi) determined according to ASTM D790A on samples nucleated with 0.1% sodium benzoate.

7. The film of claim 1 , characterized by containing less than 1 total gel having a size of 1 micron or larger, wherein the gel content is determined by optical microscopy at 8× magnification of a 5 cm square of a blown film having a thickness of 38.1 microns (1.5 mils).

8. The film of claim 1 , having a tensile strength at break MD determined according to ASTM D882 of greater than 60 MPa, and a tensile strength at break TD determined according to ASTM D882 of greater than 60 MPa for a 40 micron film.

9. The film of claim 1 , having an elongation at break MD determined according to ASTM D882 of greater than 650%, and an elongation at break TD determined according to ASTM D882 of greater than 650%, for a 40 micron film.

10. The film of claim 1 , having a 1% secant modulus MD determined according to ASTM D882 of greater than 550 MPa, and a 1% secant modulus TD determined according to ASTM D882 of greater than 550 MPa for a 40 micron film.

11. The film of claim 1 , having a two point bending stiffness bending modulus at 10°-25° of greater than or equal to 550 MPa, using an 80 micron film determined according to DIN 53121.

12. The film of claim 1 , having a two point bending stiffness of greater than or equal to 1.6 mN-mm, determined using a 40 micron film according to DIN 53121.

13. The film of claim 1 , having an Elmendorf tear strength in the machine direction (MD) of greater than 2.0 g/μm for a 40 micron film, greater than 4.5 g/μm for an 80 micron film an Elmendorf tear strength in the transverse direction (TD) of greater than 13.5 g/μm for a 40 micron film, greater than 13.5 g/μm for an 80 micron film, or a combination thereof, when determined according to ASTM-D1922.

14. A multilayered film comprising at least one layer formed from the film of claim 1 .

Assignees

• Exxonmobil Chemical Patents Inc

Inventors

• Abubakar Saifudin M
• Meka Prasadarao
• Ohlsson Stefan B

Classifications

• C08L2314/02

  Ziegler natta catalyst · CPC title

• C08J2323/12

  Polypropene · CPC title

• B32B2439/70

  Food packaging · CPC title

• C08J2327/12

  containing fluorine atoms · CPC title

• C08F210/06

  Propene · CPC title